In the related art, in a production line of a semiconductor device such as an IC, an LSI, and a VLSI, for example, as a member which is used in a strict condition which is exposed to halogen-based corrosive gases such as chlorine and fluorine and the plasmas thereof, a member and a component formed of ceramics such as an alumina has been widely used. For example, as the ceramic component in the semiconductor producing device, an electrostatic chuck, a clamp ring, a focus ring, an etching electrode or the like is adopted. As a material forming the components, a ceramic material having improved resistance to corrosion is suggested (for example, see PTL 1 and PTL 2).
Furthermore, in a process of using the halogen-based corrosive gases and the plasmas thereof, a member such as the etching electrode and the focus ring in which the electrical conductivity in addition to resistance to corrosion is required, is used. As such a member, for example, a member in which carbon nanotubes are added to an insulating ceramic such as aluminum oxide or a member in which silicon carbide is added to aluminum nitride is suggested (for example, see PTL 3 and PTL 4).
Thus, in a case of adding the silicon carbide as the electrical conductive material, silicon carbide itself does not have sufficient resistance to corrosion against the halogen-based plasma, and the particle shape of silicon carbide is a spherical shape. Thus, in order to exhibit electrical conductivity, there is a need to set the content of silicon carbide to 20 volume % or more with respect to 100 volume % of aluminum nitride as a base material. However, when the content of silicon carbide is 20 volume % or more, there is a problem in that the resistance to the corrosion of a composite material formed of aluminum nitride and silicon carbide to halogen-based corrosive gases and the plasmas thereof is greatly lowered.
Furthermore, in a case of adding carbon nanotubes to the insulating ceramics, dispersion properties of the carbon nanotubes are degraded, and thus there is a problem in that the resistance to corrosion of the halogen-based plasma and the electrical conductivity are lowered.
Thus, in order to solve the problems mentioned above, a sintered object has been suggested which contains yttrium oxide or yttrium-aluminum composite oxide, and fibrous carbon, in which the fibrous carbon is three-dimensionally dispersed in a grain boundary of yttrium oxide or yttrium-aluminum composite oxide, and has a aggregation diameter of the fibrous carbon of 10 μm or less (PTL 5).
The sintered object can prevent a decline in resistance to corrosion and electrical conductivity under a halogen-based plasma atmosphere.
Furthermore, in the related art, in a member of the plasma processing device used in a production line of a semiconductor device such as an IC, an LSI, and a VLSI, a member such as a power introduction window, a gas dispersion plate, and a wafer holding electrode needs to be supplied with high frequency electric power from a power source in a transmission manner. Thus, the members are constituted by a material behaving as an insulator to the direct current, that is, dielectric.
As the dielectric, aluminum oxide (alumina) and ceramics such as a silicon carbide are used, since those elements cause low pollution of the wafer and have excellent resistance to corrosion of the plasma.
Recently, as the material having excellent resistance to corrosion of the fluorine-based plasma, yttrium oxide (yttria) has been considered.
Meanwhile, in the etching processing in the semiconductor production process, in addition to the plasma of the reactive gas, a method of applying high frequency to the processing wafer as bias electric power has been generally used. In this method, bias electric power is superimposed on the electric power of the plasma, and the electric potential of the plasma fluctuates in a direct current manner. However, since the device material is an insulating material to the direct current, the electric potential fluctuation of the plasma is not alleviated, and thus, an electric field is generated in the processing wafer to destroy a circuit formed on the wafer, and as a consequence, a proportion of a product which is defective may increase.
Thus, in order to suppress the electric potential fluctuation of the plasma mentioned above, a plasma processing device has been suggested in which a surface section through which plasma is directly seen in a reaction chamber inner wall is covered by the dielectric, an electrical conducting section is provided in a part of the dielectric covering section, and a DC earth is provided in the electrical conducting section (PTL 6). As the DC earth, aluminum alloy, stainless steel or the like is used.